Automatic telephone system



B. D. WILLIS. AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED APR.8.1914. RENEWED AUG. 1, 1918. 1,345,054, PatentedJune 29, 1920.

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AUTOMATIC, TELEPHONE SYSTEM.

APPLICATION FILED APR. 8. I9I4. IIENEwED AUG. I. 191s.

1,345,054. 'Patented June 2.9, 1920.

2 SHEETS-SHEET 2.

ffl 3 IIIIIIIIIIIIHII' UNITED STATESA :PATENT OFF-ws BERNARD D. WILLIS,0F CHICAGO, ILLINOIS, ASSIGNOR TO AUTOMATIC ELECTRIC COMPANY, OFCHICAGO, ILLINOIS, AOOB'PORATION ILLINOIS.

AUTOMATIC TELEPHONE SYSTEM.

T 0 (ufl whom t may conce/rn.'

Be it known that I, BERNARD D. WILLIS,"

a citizen of the United States of America, and resident of Chicago, Cookcounty, Illinois, have invented certain new and useful y means forcontrolling automatic switcheswhich include plurality of operatingmagnets, together with means for successively switching the operatingmagnets into operative position, which operating or motor magnets arecontrolled by impulses of one character, while the switching operationsare controlled by impulses of a different character.

In the accompanying drawings I have illustrated my invention inconnection with automatic selector and connector switches of well-knowntypes, and while I have shown but a single selector switch for extendingconnection to the connector, it will, of course, be understood thatsecond selectors controlled in a manner similar to that of the first-selector could'be inserted between the first selector and theconnector. In the drawings Figures 1'and 2 taken together show acomplete'circuit connection between a calling substation A and a calledsubstation A in a system embodying the principles of my invention.

Fig. 3 is a view showing a portion of the impulse-transmittingmechanism. l

Referring to Fig. 1, there is shown a subscribers substation A, the lineconductors of which terminate inthe individual or line switchC. Thisline switch is one of a group of similar line switches, the plungers(not shown) of which engage a shaft and are controlled by the operationof the master switch D in such manner that they are, when in normalposition. held directly in front of the terminals of an'idle trunk lineleading to a selector E. The selector E is the means for extending theconnection to Specification of Letters Patent. l kvPai-,enilnl une 29,1920, Application filed. April 8, 1914, Serial No. 830,399.RenewedAugust 1,v 1918. Serial No. 247,862. v

scribers'line A. c l

The subscriber-s substation Amay be of any suitable or approved type andcomprises the usual receiver 2, transmitter 8, ringer 4 and condenser'5. It is also provided with a suitable impulse-sending device similar tothat shown and described in British Patent No. 29,654 of 1910, issued toS. G. S. Dicker, except that two-extra impulse springs are added,together with means for controlling the same. Referring Yto thesubstation A, the impulse-sending device comprises a pair of impulsesprings 6 and 7, apair of auX- iliary impulse springs 9 and 10 and animpulse wheel 8, whichv latter is controlled .through the medium of afinger hole dial fthe connector switch II (Fig. 2), which4v completesthe connection to the called sub- (not shown) in such a manner that theimpulse springs 6 and 7 may be momentarilyl separated a number of timescorresponding to the digit called to transmit a plurality of impulsesover the line, and which impulses are then followedby one or more rapidimpulses transmitted by the impulse springs 9 and 10. Referring to Fig.3, a pawl 12jis securedvto therotatable portion 11 of the dial, one endof which pawl is held in normal position against the pin 13 by a spring14. When the dial-is rotated in a counter-clockwise direction, the pawlv12 strikes the, spring 10 in such a manner as to tilt the said pawldownward, thus allowving it to pass the spring 10`without causing it to'break Contact with the springV 9; but

when the dial is released and the rotatable portion 11 rotates back tonormal, one or more impulses are transmitted over the line conductors bymeans of the impulse springs `6 and 7; then, just before the dial Vhasreturned to normal position, the pawl 12 engages the spring 10 (as shownin Fig. 3)

.and iexes it to the right until the pawl- 12 has passed beyond the saidspring. The instant the pawl 12 releases the spring 10, it flexes to theleft. and separates from the spring 9, sending one or more quick or highfrequency impulses. It is, of course, understood that any suitable dialor call-sending device may be used and that I do not wish to limitmyself tothe exact construction shown herein.

. rvThe subscribers individual switch C is of the general type ofsubscribers switch shown` in Britishpatent to R. W. James No.

' "eral 'type of Yselector switch disclosed in ing to a selector switchE. Each trunk line' 26,301 of 1906, being, however, of the particulartype shown in British patent to T. Gr. Martin No. 1419 of 1910. Thisline Y so constructed that -the magnetic circuit of the windings 18 and19 is separate from that ofthe windings 20 and 21. AThe winding 18operates both theplunger arm 15 and the cut-off armature 16, while thewinding 19 is only strong enough to operate the cutp' armature 16 and tohold the plunger arm 15 in its operated position. Vhen the plunger arm15 is operated, the plunger is forced into a bank of contact springs,forcing the springs 23, 24, 25 and 26 into engagement with the springs27, 28, 29 and 30, respectively. VAlthough Vonly one set Yof springs(23-30) is shown, each line switch is provided with a plurality of suchsets, eachset forming the terminal of a trunk line leadjis connected inmultiple with the corresponding springs of all the line switches oflfunction of the master switch, as is well kn'own,ris to maintain theplungers of all the idle line switches 1n positlon to engage theterminal `of an idle trunk line.

The first selectorswitch E is of thegen- United States Letters PatentNo. 815,321,

lgranted luarch 13, 1906, to Keith, Erickson and Erickson, except vthatthe so-called side y ries.

switch is omitted and the'circuits Vare modified to adapt the switch tooperate in a system in which it is controlled by impulses delivered overthe two sides of the line in se- Among other details, the seelctor Ecomprises a bank of contacts arranged in rhorizontal rows or levels,which contacts are y switch are .controlled through the medium of 'thedouble-wound line relay 36. Means Vfor permitting the switch to berestoredto normal position is provided in the release magnet 37, which,upon energizing, withdraws the retaining pawls from the shaft in thewell-known manner. Springs 38 and 39 are also provided, which springsclose only when the switch shaft has been raised one ormore steps fromits lowest position. The circuit of the release magnet 37 is controlledby the relay 40, which relay is a slow acting relay, c., it is slow toenergize when its circuit has been completed. The said relay will notrespond to ordinary impulses of current, but requires a steady flow ofcurrent to operatively energize. When the line relay 36 energizes, itcloses the circuit of the relay 62, which is connected in series withthe relay 63. This latter relay, however, is normally short-circuited bythe springs 41 and 42 of the line relay36. The spring 41 is so adjustedand constructed as to follow the spring 42 when the relay 36 isenergized.

Should one or more impulses of ordinaryY duration be transmitted throughthe line relay 376, the springs 41 and 42 will operate in 42 will beseparated for an instant due to the fact that the spring 41 is unable tofollow the'rapid vibrations of the spring 42. The relay 62 also controlsthe circuit of a relay 88, and a switching relay 86 is provided forcutting the connection through to the wipers 31,32 and 33. Theconstruction and operation of the switch will be hereinafter more fullyexplained in connection with the description of the manner in which aconnection is established between a calling and a called line. I

The connector switch l-l (IF ig. 2) is of the same generalV type ofconnector switch as disclosed in United States Letters Patent yl\lo.,81',176, granted March 13, 1906, to

Keith, Erickson and Erickson, the circuits, however, being vnfiodiliedto adapt the switch to operate in a system inV which .the central oiiiceapparatus is controlled by impulses delivered over the two sides of theline in scries. Like the selector, the connector is provided with ashaft (not shown) carrying the wipers 45, 46 and 47, which shaftcontrolled by the vertical magnet 48 and the rotary magnet 49V which arein turn controlled bythe line relay 52. The usual side switch comprisingthe wiper 50 controlled by the private magnet 54 in the usual well'-known manner. The magnet 51 is the usual release magnet. The line relay52 is con.- nected with the line through the reversing springs of theso-called back-bridge relay 53, through the windings of which latterrelay the called line is provided -with talking current. The springs and56 con trolled by the line relay 52 operate in the' there is shownk thebattery B having one armature.

same manner as hereiiibefore described for termina-l grounded -at G. AtQ there` is shown a busy signaling machine which pro` vides a busysignal, said busyL signal being applied to the calling line through themediumo'f the busy relay 60 in case the called line is in use. i

The substation shown at A 'and' the line switch C are similar in allrespects to the substation A and the line switch C'.

Having given a general description of Vthe apparatus, in order to give aclearerunder- Y standing of the operation of the system, it

will now be described inV detaill how the calling subscriber atsubstation A may obtain connection with the subscriber at the calledsubstation A. We will assume that the number of the called substation is220.

Upon the removal of the receiver at the substation A a circuit is closedthrough the line winding 21 of the individual switch C, therebyattracting the line armature 22.

The armature 22, uponxbeing attracted,`

closes a circuit through the'pull-down coil 18 in series with theauxiliary windingV 20. The pull-down coil, upon energizing, at-

tracts the plunger arm 15 to force the plunger into the bankof springs23 to 30, inclusive. It also operates the cut-olf armature 16, therebydisconnecting the line winding 21 from the line, The armature 22 doesnot fall back immediately, however, owing to the fact that the winding20 is still in series with the pull-down winding 18. Upon the plungerarm 15 being attracted, the

ysprings 61 are brought into engagement to short-circuit the auxiliarywinding 20, making the same slightly slow acting. The armature 22 beingslow to fall back allows suliicient time for aholding circuit to beclosed in the switch rahead for the cut-off or holding winding *19.v Theengagement oit the springs 23 and 26 with the springs 27 and 30,respectively, extends the subscribers line to the line relay 36 of theselector switch -The line relay 36 oi the selector switch E is thereuponenergized,iclosing a circuit through the relay 62. 4The circuit extendsfrom' ground G through the springs 43,

42 and 41, springs 64 and 72 of relay 63 throughthe said rela, 62 to thebattery lead 100, thence throng battery B to ground G. The relay 62,upon energizing, closes the relay 88 extends `from ground theabove-mentioned holding circuit through the cut-oil1 winding 19 of the"line switch C.' This circuit extends from ground G3 through the contactof springs 67, 66 and 65, springs70 and 69,'bank springs 28 and 24 andthe said holding winding 19 to the battery lead 100. The winding 19,upon energizing, holds tlie.,arinatu1'e 16 and the plunger arm 15intheiroperated positions after the circuit or' the pull-in`w1nding is 'brokenby the falling back of the line arinature 22. Af guarding groundpotential 4is supplied to the connector private bank con- Y tacts ofthecalling line as soon as the relay 62 is energized. the circuit justVtraced to the .bank spring 24, thence over the conductorv 71 to saidprivate bank Contact. A further result of the cnergization'of the relay62 is to close a locking circuit for itself and` to close a circuitthrough the relay 88. The locking circuit `for the relay 62 extends fromground G3 through the contact lof springs 67 and 66, springs 73, springs42A and 41, springs 64yand 72 and the said relay 62 tothe battery lead100. The energizing circuit for G3 through the contact of springs 74 and75 and the relay 88 to the battery lead 100. The relay 88, uponenergizing, closes a locking circuit for itself `after springs 39 areclosed, extending from ground upon the release trunk 77, springs 78,off-normal springs 39, springs and 81 and through the said relay 88 tothe battery lead 100. The'apparatus is nowl in readiness to digit,

The calling subscriber now operates his calling device for the firstVdigit 2 of the called number, whereby the substation impulse springs 6and 7 are separated twice,

receive impulses for the first followed by one or more high speedimpulses transmitted by the impulse springs 9 and 10. The line relay 36,responding to the two impulses sent by the impulse springs 6 and 7,denergizes twice, which operation transg mitsv two impulses of currentthrough the vertical magnet 34.v The circuit for these impulses extendsfrom ground G4 through i the contact oi'springs 83, springs 84,.springsand the said vertical magnet 34 to the battery lead 100. It will be seenthat the relay 40 receives impulses at the same time, but it is notoperated, as it takes a steady flow of current to operatively energizethe said relay. The vertical magnet, receiving the two impulses overthis circuit, operates to raise its switch shaft and wipers two stepsopposite the second row or level of bank contacts. The high speedimpulses which ol low the two impulses just transmitted by the impulsesprings 6 and 7 cause the armature of the line relay to vibrate veryrapidly. As hereinbefore stated, this causes the This circuit extends'overY`v springs 41 and 42 to be separated for an in- 130 41 and 42 cometo rest.

stant, which causes the relayv 63 to be operthrough the contactofsprings 67 and 66,

. springs 73, relay y63 andthe relay 62 to the battery lead 100. Therelay v63upon energizing, opens the shunt around itself at the springs72V and64, `thus preventing it from again becoming shunted when thesprings A further result due to the energization of the relay 63 is toclose a'locking circuit for itself, shortcircuit the relay 62 and placea new holding ground upon the trunk-release conductor 77. The saidlocking circuit for the relay 63 extends from ground G. through thecontact of springs 43fand 42, relay 63 and the springs 72 and 71 to thebattery lead 100. The short-circuiting of the relay 62 causes the sameto denergize, thereby closing a circuit through the rotaryl magnet 35.This circuit extends from ground G5 through the contact of springs 68and 69, springs 78, off-normal springs 39, springs 80 and 81, springs 75and 76, springs 79 and the-said rotary magnet 35 to the battery lead100. The rotary magnet, upon `energizing, rotates the Wipers one step,and by opening the springs `79 and 78 disconnects ground G5 from itselfand from the relayy 88. It the first trunk line of the second level isidle, the relay 88 denergizes immediately, but if this trunk line isbusy, the private wiper 32 inds the contact with which it engagesprovided with a guarding ground potential which istransmitted to therelay V88 through 'the springs 80 and 81, thereby preventing it fromdenergizing. The rotary magnet, however, denergizes when the` springs 79disengage, regardless of whether the relay 88 remains energized or not.If the relay 88 remains energized, the circuit of the rotary magnet willbe again closed as Vsoon asthe armature drops vback far enough to closethe springs 79. The rotary magnetwill therefore operate in the manner ofa buzzer to advance the wipers step by step over the contacts until theynongrounded contact of an idle trunk line is reached by the wiper 32,whereupon the relay 88 denergizes. The relay 88, upon deenergizing,whether after one or several operations of the rotary magnet,permanently breaks the circuit ofthe magnet 35 and closes the circuit oftheswitching relay 86. The circuit through said relay extends fromground G5 through the contact of springs 68 and 69, springs 78,off-normal springs 39, springs 80 and 482 and the said relay 86to thebattery lead 100. The relay 86, upon energizing, extends the callingline through the wipers 31 and to the line relay 52- of the connector Hand disconnects the line relay 36 from the said calling, line.

VrThe line relay 52, upon energizing, closes a circuit through the relay87. This circuit 54 and to also prepare a circuit for the vertiextendsfrom ground VGG throughV the contact of springs 57, 56 and 55, springs89 and the lower winding of the relay.87.,to battery B. The relay 87,upon energizing, closes a holding circuit lor .the relay 86 of theselector@ and the holding winding 19 of the line switch G. The saidcircuit for the-relay 86 extends `from ground G7 through the contact'ofsprings 103 and 104, springs 93 and v94, conductor 91, wiper 32, springs80 and 82 andthe said relay 86 to the batteryA lead 100. The holding.circuit for the holding winding 19 extends over the circuit just tracedto the wiper 32, thence through the orf-normal springs39, springs 78,bank springs 28 and 24 andthe said winding to the battery lead l100. Theadjustment of the relays 88 and 63 is such that the relay 87 or' theconnector H will be energized and provide a holding ground 'for thetrunk-release conductor 91 before the relay 63 denergizes. A furtherresult of the energization of the relay 87 is t0 close a locking circuitfor itself and'vfor the private magnet cal magnet 48 by the closureofthe springs 95. The said circuit extends from ground G7 through thecontact offsprings 104 and 103, Y and the springs 94,93 and 96. Here thecircuit divides, one branch extending through the upper winding of therelay 87 to battery Y B, and the other circuit extending through thecontact of' springs 97 and the private magnet 54 to battery B. Theapparatus is now in readiness for the operation of the dial atv thecalling substation for the second digit 2. lhe calling subscriber nowoperates his calling device for the second digit 2 of the called number,whereby the substation im- 105 pulse springs 6 and 7 are separatedtwice, followedby one orl more high speed impulses transmitted by theimpulse springs 9 and 10. The line relay 52,.responding to the twoimpulses sent by the impulse springs 6 and 7, is denergized twice,therebysending two impulses through the vertical magnet 48. Thiscircuitextends from ground G6 through the springs 58, springs 95, .verticalmagnet 48 and the side switch wiper 115 50 (in first position) tobattery B. The relay 99 also receives impulses of current at this time,but it is not operated, as this relay does not respond to the impulsesof Vcurrent. The vertical magnet being thus operated steps the switchshaft and wipers up two steps opposite the second row orlevel of bankcontacts. The high speed impulses that follow cause the armature oftheline relay 52 to vibrate very rapidly, which op- 125 erationgcausesthe springs 55 and 56' to separate for an instant in the mannerVheretofore described, whichoperation allows 'the Vrelay 101 to energize.The circuit for this Contact of springs 57 and 56, relay 101 and'r thelower winding of the relay 87 to battery B; The relay 101, uponenergizing, opens the shunt itroin aroiindfitsel'f at the springs t9 andopensthe circaiitoiE the private magnet ilat the springs 97. rllheprivate magnet 51, upon deenergizing, allows the side switch to advancefrom first to second position. yThe movement` oi the side switch wiper50 from vlirst to second position transfers the battery connection fromthe vertical magnet L18 to the rotary magnet49. The calling subscribernow operates his calling device lor the last digit 0, in response Atevwhich the coiinector'line relay operates to transmit tenl impulsesthrough the rotary r agnet L19 to battery B. The circuit of the.'

relay 101 'is opened upon thel irst denergization of the relay `Therelay 101,Y

upon deenergizing, again closes a circuit through the private magnet 54at the springs 97 and places a shunt around itself at the Y springs 89QThe rotary magnet, responding (saV to Vthe ten impulses transmitted bythe line relay 52, operates to rotate its wipers onto the contact or thedesired`-liiie.

ture ot the line relay152 to vibrate very rapidly, thus causing thesprings and 50 `to separate 'for an instant, which allows. the relay 101to again energize. The relay 101, upon energizing,V opens the shuntaround itself at the springs 99 and opens the circuit et the privatemagnet 54'at` the springs 97. The private magnet A5&1, upondeenergizing,allows the side switch yto advance one more position, .je.,from second to thirdposition. By 'the engagement of the side switchwiper 50 with its third-posi- 'tionV contact point, a circuit is closedeX-f tending ironi'ground G7 through the contact of springs 104 and 103,springs 93 and 9i, springs 106, relay 107, lower winding` oit tl'ieielay,G0 and the iside switch wiper 50 'third position.) to batteryB. Therelay does not receive sufficient-current when connes ,ed inserieswiththe relay 107 to operativelyr energize. The relay 107v extends the calllthrough cut-oft winding 111 extends' from` ground Gllthrou'gh thecontactof springs 109 and 110, privateV wiper 4117, conductor 115 and thesaideut-oil winding 111 to battery B.

.The ,circuitr'forythe ringing relay extends :trom vground G11 throughthe,V Contact of springs 109 fand 108, springs 116 and'119,

ringing relay 112-and the interrupt'er 117 to batteryB. 'Theringing-relay, upon energizing," disconnects the calling line from'` Thehigh speed impulses .that follow cause the armarent generator 'Racrossthe .called line t0 signal the called subscriber.

the medium of the interrupter 117. Uponv the, response of the calledsubscriber his line is provided with talking current throughV thewindings of the back bridgev relay 53, which relay, upon energizing,closes a cir-V cuit through the upper winding of the relay (30. Thiscircuit extends `fromground G12 through thevcontact of springs 118,throughfthebupper winding of said relay and the side switch wiper 50`(in third position) vto battery B. The two winding of the relay 60assist eachother and the said relay is operatively energized. The relay60, upon energizing, opens the'circuitpof the ringing relay 112 at thesprings 116 and 119 and closes ya locking circuit for The ringing relayis energized intermittently through itself through the springs 116 and120 in# is completed, 'theA4 connection isreleased by the hanging up ofthe receiver. at the calling 'substation in the following manner:VVhen'tlie receiver at the substation A Ais restoredtotheswitchhook, theseparation of the"hookswitch i Y springs destroys the energizing circuitofthe connectorr line relay 52,. The line relay 52, vupon, denergizing,closes a circuit through" the relay 99, which relay is slow to energize.

The said circuit extends from ground G through the Contact of springs58, oft-nor-` mal springs 121 and, the said relay 99 to bat-r tery Therelay 99, upon energizing, closes a circuit through the release magnet51 from ground G7 through the contact of springs' 104 and 105 and thesaid releasey magnet 51 tobattery B. The magnet, upon energizing,restoresthe switch shaft and sideswitch wiper to normal position and itsown circuit is broken by the denergizing of theY relay A99, which iscaused by the separation ofthe off-normal' springs 121 when theshaftreaches its ,lowest position. A furlther result due to theenergization of the relay 99 isthe-opening of the circuit of therelayf87 at the springs 104'and 103. The relay 8,7, upondeenergizing,opens the holding circuit forthe relay 86 ,of the selector E and the.holding` winding .19 of the line switch Cif The relay. 86, upondenergiz'ing, closes a circuit through the release relayA 410'. Thiscircuit extends from ground G4 through `thencontact of springs S3,springs 84,01%

Ves

net 37 to the batteryy lead 100. The selector E releases, breaking thecircuit of its own release magnet when theshaft reachesits lowestposition. The winding 19 o f the line switch C, upon becomingdenergized, allows the plunger arm 15 to return to normal position Itno'w having been explained how one subscriber establishes connection and`releases thesame, it will be explained 'how' a connection is preventedfrom being made with a busyy line and :how the calling subscriberreceives a'busysignal when calling a busy number. If the number called1s busy, thererwill be ar guarding potentialV upon the connector privatebank contact, justas explained in connection with theY line switch C.The connector private wiper, upon engaging this guarding contact and atthe instant the side switch passes to third position before the circuitof the private magnet 541 is broken, completes a circuitthrough therelayL 60. This circuit extends from ground on the said private. wiper47 through the contactof springs 110 and123,

the lower winding of said relayOfand the side switch wiper 50 to batteryB. The relay 60, upon energizing, closes'a locking circuit for itselfextending from ground G7 through the contact of springs 1011 and 103,l

springs 93 and 94, springs 124 and 120, up-

per windingof the relay 60. and through the side switch wiper 50 (inthirdposition) to battery B. y rA further result due to the energizationof the relay .60 is the giving of the busy signal to the callingsubscriber. 1 This upon the hook, thereby releasing the connection inthe manner above described.'

It will thus be seen that lI "have devised a very efl'icient tele honesystem in Vwhich the A automatic se ector and connector switches areprovided with motor magnets controlled by Vas'eries of impulses ofL onecharacter, while the Vswitching operations of said switch are controlledby impulses impulses are 'transmitted tothe automatic switches over twosides of metallic line circonnection with certain vtypes ofautomaticswitc'lie s,'it will, of course, be understood that invention is notvlimited to Vswitches y sively bring said operating magnets under veration of said second magnet. of a different character. Further-more,these intacta f of this type, but is equally as well ladapted for use inconnection with other systems which require separate and distinctoperations over a single circuit. Y

What I claim as my invention is :mi 1. In atelephone system, anautomaticV switch having a plurality of operating magv nets, means forswitching a connection from one to the othery of said operating magnets,means including an yimpulse controller and an impulse circuit over whichcurrent flows when closed for controlling said operating magnets byimpulses of one character over said circuit, and for controllingsaidswitch- L ing operation by impulses of a second Vcharacter kover saidcircuit, the resistance of the circuitwhen thus closed being the same inboth operations.v

.2. In a telephone system, an automatic switch having a plurality ofoperative movements, and means for controlling the operation of saidswitch by va series of impulses of one frequency, followed by one ormore rapid impulses. j j

, E. In'v a telephone system, `an automatic switch having a plurality ofoperating ele! ments, means for switching the connection from one to theother of saidoperating elements, means forl controlling said operatingelements by impulses of one frequency, and means for controlling saidswitching operations by one Yor more rapid impulses.

4, In a telephone system, an'automatic switch, a trunk line extendingthereto, said.l switch including a line relay anda plurality ofoperating magnets, means foroperating. said line relay by impulses' ofone character vto control the voperation of sadswitch, and means foroperating said line relay by impulses oi. a different character tosuccesthe control of said relay.. y Y o 5."In a telephone system, anautomatic switch, a trunk line extending thereto, a line relay, a pairof operating magnets,'means for transmitting` a plurality of ,impulsesVVthrough said line relay to control the operaf i tion of one of'saidoperating magnets, and` meansl for then transmitting one or more rapidimpulses through said vline relay fto bring said second operating magnetunder;V the control of said line relay, said iirst means orfthentransmittingone or more impulses through said line relay tocontroltheop- 6.,-In a telephone system, an automatic switch including aplurality of operating magnets,`as`ide switch Vfor successively con-Vtrolling the circuits ofsaid magnets, means for controlling theoperationorsaid mag-12H5V I nets by impulses of one character, and meansY for controllingthe operation of said side switch by one ormore rapidimpulses. y l7. In'a telephone system, a line circuit,`

an automatic switch having a 'pluralityof-l operating magnets, means forswitching a connection from one to theother of Vsaid operating magnets,means including an iml p ulse'controller and an impulse circuit overwhich 'current flows whenclosed for controllingsaid operating magnets bythe impulses of one characterover saidcircuit, and for controlling ksaidswitching operation by impulses of'a: second character `over saidcircuit, said impulses 'being transmittedoverk two sidesof said linecircuit in series, theV resistance of the circuit when thus closed beingthe same in both operations.

8.111 a 'telephone system, a line circuit,

an automatic switch having a plurality ofV operative movements, andmeans forcentrolling the operation of said switch by a series ofimpulses of one frequency, followed vby one or more rapid impulses, saidimpulses being transmitted over twQsides of said line circuit in series.i

9. In a telephone system, a line circuit, an automatic switch having aplurality of operatingk elements, means for switching the connectionfrom one to the other of said operating elements, means for controllingsaid operating elements by impulses of one frequency, and. means forcontrolling said switching operations by one or more rapid impulses,said impulses being transmitted, over two sides of said line circuit inseries.

10.111 a telephone system, an automatic a switch, a 4trunk lineextending thereto, said i switch including a line relay and a pluralityof operating magnets, means for operating said line relay byimpulses ofone vcharacter to control lthe 'operation of said switch, and meansy foroperating said line relay by im'- pulses of ab different character to'successively bring Vsaid operating magnets under the control'of saidrelay, said impulses be#` ing transmitted over a circuit including twosides of said trunk line in series.` j i 11. In a telephone system, anautomatic switch, a trunk line extending thereto, a

line relay, a pair of operating m.agnets,

means for transmitting a pluralityo'f impulses through said line relayto control the operation of one of said operating magnets,

said magnets by impulses of one character,

and means for controlling the operation of said side switch by one ormore rapid im pulses, said impulses being transmitted over two sides ofsaid line circuit in series. i

13.111 a telephone system, `a conductor and a source of current forminga iii-cuit, a

ltelephone for said circuit, an impulse sender for said circuit, line, atelephone .for said line, an automatic switchy associated with f saidcircuit, a relay and propelii'ngmagnets for said switch, means includingsaid'sendei for variably affecting the frequencyof energizations of saidrelay for controlling said magnets to build up a talking circuitvbetween'said circuit and said lin-e and means forfdisconnecting saidrelay vand for substituting another relay through which current fortalking purposesis supplied to the said talking circuit. i Y

14. In a telephone system, an automatic switch having a pluralityofoperating inag-r nets means for switching a connection from one'to,the othervoffsaid ope ating magnets,

means for controlling said 'operating magnet by impulses 'ofonecharaeter, means for controlling said switching operation by im-`pulses of4 a second character, and means for producing said impulses bybreaking the .line circuit. f

15. In atelephoneexchange-system, the combination with an. automaticswitch, means for directing the action of said switch in responseto-curreut impulses ofv acertain frequency, of meansfor said switclilresponsive to current impulses of a, different fre?- quency for shiftingthe directive means, substantially as set forth.

VlG.In a telephone system, a subscribers line, a plurality of automaticswitches, an impulse transmitterat the station on rsaid line adapted tocontrol the-variable setting of said switches by impulsesproduced in theline circuit andl to cause the change over from one of said switches tothe next by an vimpulse of shorterlduration thanthe setting impulses. wvi li'. In a telephone system,a subscribers line, a plurality ofautomatic switches, an

impulse sender at the substation 'on Vsaid yline adapted'to produce auniform series of interruptionstherein to control the variable settingof said switches and to cause the change over from one switch to thenext` by a short interruption following each se'- ries.

18. In atelephone system, an automatic switch having a plurality ofoperative pinovements, and means for controlling the operation of saidswitch by a series of impulses of uniform duration, followed byanimpulse of shorter duration. Y'

v19.v InA a telephone system, an automatic switch having 'a plurality ofoperating elements, means for switching the connection from one to theother ofsaid operating elements, means .for controlling` said operatingelements by' impulses of a certain length, and means for controllingsaid switching means by an impulse of lesser length.

20. In a telephone system, an automatic switch having azplurality ofoperating ele-Y ments, means lor switching the connection from one tothe other oit said operating elefor producingsaidv impulses by breaking4the line circuit.

21. In a telephone system, a subscribers line, means l'or extending saidline comprising an automatic switch, primary and secf ondary operatingmagnets V in said switch, meansI for producing successive series ofiinpulses of a particular duration inthe line Vcircuit to cause thesuccessive operation of said magnets, andv meansv for causing the changeover from one magnet to the other by an impulse. ofl shorter durationthan the operating impulses.

22.111 a telephone system, an automatic'.

switch having primary and secondaryV oper- Y ating magnets, a'contiolrelay anda circuit therefore, meansxfor transmitting successive i seriesoimpulses over said circuit, whereby said magnets'may besuccessively.;operated.

undercontiol of said relay, means for transmitting anL impulse l ofshoiter `duration sponsive to said short impulse for shifting -thecontrol fof saidrelayf-from one magnet to the other.y Y Y 23.y In `atelephone system, subscribers lines, an automatic connector switch,means for'o'perating said switch toconnect with a dcsired called line,test andv switching relays in said :connector adapted, respectively, to

give the calling subscribera busy signal and to complete connection to acalled line, means for ycompleting a-circuit through said relays in'series after the connector has operated, said test `relay being normallyunresponsive thereto, and Va test Wiper conoperating with` the testcontact ol the called line -tocause the Venergization of one orftheViiected to the junction of said relays and cof other of said relays,depending onwhether prising talking conductors, means for operat-ingsaid `switch to connect said-conductors with a desired called line,aswitching relay in said connector controlling contacts in n saidconductors, a Vtest relay, acircuitcomis established f the yjunction ol'said relays, test contacts lor said,V lines, anda busy potential onthetestKY contact o' thercalled lineif-the saine is :in

use, whereby the saidrswitching relay will be short circuited andthesaid test relay will be energized by way ofsaidjtest wipeiz 25. In a itelephone system, subscribers lines, anyvautomatic connector switch,means for operating said switch to conii'ectwith a desired called line,test and switchingrelays '-gized thereafter .to close a circuitthi'oughthan the*A operating impiilses,'and means re said relays in series,andatest wiper'connectcd to the, junction 'of said relays and coL operatingwithV thc test contact of the calledV line to cause the energization ofeither the-' said test relay 'or the saidswitching'relay,

depending on whether the called-lineiis busy or idle.

' Signed by me at Chicago," Cook. county,

Illinois, this 2nd dayV of April, 1914.'-

llVitnesses:

HERBERT W. KRACKE, ,y B. GARBER.

BERNARD, D; WiLLis,

